ABSTRACT
Objective To evaluate the effect of methylprednisolone on endoplasmic reticulum stress in rats with ventilator-induced lung injury ( VILI ) and the relationship with phosphatidylinositol 3-kinase∕serine-threonine protein kinase ( PI3K∕Akt) signaling pathway. Methods One hundred clean-grade male Sprague-Dawley rats, aged 4-5 months, weighing 270-320 g, were divided into 5 groups ( n=20 each) using a random number table method: control group ( C group) , VILI group ( V group) and different doses of methylprednisolone groups ( M1-3 groups) . Group C received no mechanical ventilation and kept spontane-ous breathing for 4 h. Rats were mechanically ventilated ( tidal volume 40 ml∕kg, respiratory rate 15-17 breaths∕min, inspiratory∕expiratory ratio 1 : 1, positive end-expiratory pressure 0, fraction of inspired oxy-gen 21％ during OLV) in group V. Methylprednisolone 2, 10 and 30 mg∕kg were intravenously injected at 20 min before mechanical ventilation in M1-3 groups, respectively, and the equal volume of normal saline was given in group V. Blood samples and lung tissues were taken at 4 h of ventilation for measurement of the lung permeability index ( LPI) and wet∕dry lung weight ratio ( W∕D ratio) , for examination of pathological changes, and for determination of apoptosis index ( AI) in lung tissues ( by TUNEL) , expression of Akt, phosphorylated Akt (p-Akt), glucose-regulated protein 78 (GRP78), CCAAT∕enhancer-binding protein homologous protein (CHOP) and caspase-12 in lung tissues (by Western blot). Injured alveoli rate (IAR) was calculated. Results Compared with group C, the W∕D ratio, LPI, IAR and AI were significantly in-creased, the expression of p-Akt was down-regulated, and the expression of GRP78, CHOP and caspase-12 was up-regulated in V and M1 groups ( P<0. 05) , and no significant change was found in the indexes mentioned above in M2 and M3 groups ( P>0. 05) . Compared with group V, the W∕D ratio, LPI, IAR and AI were significantly decreased, p-Akt expression was up-regulated, and the expression of GRP78, CHOP and caspase-12 was down-regulated in M2 and M3 groups ( P<0. 05) . Conclusion Methylprednisolone in-hibits endoplasmic reticulum stress, thus inhibiting cell apoptosis, and the mechanism is related to activa-ting PI3K∕Akt signaling pathway in rats with VILI.
ABSTRACT
Objective To evaluate the effects of penehyclidine hydrochloride on synthesis and release of high mobility group protein box 1 (HMGB1) in macrophages induced by lipopolysaccharide (LPS) in mice.Methods RAW264.7 cells obtained from mice were seeded in the culture dishes.After being cultured for 24 h,the cells were randomly divided into 5 groups (n =6 each) using a random number table.The cells were incubated routinely in group C.The cells were incubated in the presence of LPS 500 ng/ml (group LPS),LPS 500 ng/ml + penehyclidine hydrochloride 0.5 μg/ml (group P1),LPS 500 ng/ml + penehyclidine hydrochloride 2 μg/ml (group P2),or LPS 500 ng/ml + penehyclidine hydrochloride 5 μg/ml (group P3).All the cells were incubated for 24 h.The cells and supernatant were collected.The proliferation of the cells was measured by CCK-8 assay,HMGB1 mRNA expression in the cells was detected by RT-PCR,NF-κBp65 protein expression in the cells was detected by Western blot and the concentration of HMGB1 in the supernatant was detected by ELISA.Results Compared with group C,the expression of HMGB1 mRNA and NF-κBp65 protein in the cells was significantly upregulated,and the concentration of HMGB1 in the supernatant was increased in LPS,P1,P2 and P3 groups (P ＜ 0.05).Compared with group LPS,the expression of HMGB1 mRNA and NF-κBp65 protein in the cells was significantly down-regulated,and the concentration of HMGB1 in the supernatant was decreased in P2 and P3 groups (P ＜ 0.05).Compared with group P1,the expression of HMGB1 mRNA and NF-κBp65 protein in the cells was significantly down-regulated,and the concentration of HMGB1 in the supernatant was decreased in P2 and P3 groups (P ＜ 0.05).There was no significant difference in the indicators mentioned above between group P2 and group P3 (P ＞ 0.05).There was no significant difference in the proliferation of the cells among the 5 groups (P ＞ 0.05).Conclusion Penehyclidine hydrochloride can reduce the synthesis and release of HMGB1 in macrophages induced by LPS through inhibiting NF-κB activation in mice.